Structural Studies of Enantiomers, Racemates, and Quasiracemates:  N-(4-Methylbenzoyl)methylbenzylamine and N-(4-Nitrobenzoyl)methylbenzylamine

Cocrystallization of equal portions of (R)-N-(4-methylbenzoyl)-α-methylbenzylamine and (S)-N-(4-nitrobenzoyl)-α-methylbenzylamine yields bimolecular crystals that exhibit quasiracemic behavior. Derived from a slight chemical modification of one component of the “true” racemate, this quasiracemate compound extends the current knowledge base of structural features responsible for the construction of quasiracemic molecular arrays. A crystallographic comparison of the quasiracemate structure with its enantiomeric components and racemic counterpartsa total of five structuresdemonstrates the importance of molecular shape to the self-assembly of crystalline architectures. Inspection of the quasiracemate structure reveals local molecular packing that closely mimics the centrosymmetric alignment of the racemates. Unlike our prior investigations of the quasiracemate phenomena, however, the current set of enantiomeric, racemic, and quasiracemic compounds lacks any prominent long-range isostructural correlation as in...